LAST NAME___________________________ First Name _______________________ BIOLOGICAL SCIENCES 330L Midterm Exam III Spring 2006 Apr 3 (11:00-11:50 am or 12:00 noon-12:50 pm) Prof. John Petruska This exam (worth 175 points) is on five (5) pages Please answer all questions in the space provided. Please write your name and lab information below and also write your name on every page of the exam. Last Name _______________________________ First Name ________________ Lab Section (time and day)________________________ TAs _______________ SCORE 1. (30) ________ 2. (30) ________ 3. (40) ________ 4. (35) ________ 5. (40) ________ TOTAL (175) __________LAST NAME___________________________ First Name _______________________ Page 1 ______ 1. (30 points). Each blank correctly answered is worth 1 pt. (a) (5 pts) Plant cell _______________ capture solar energy to produce glucose and oxygen gas from carbon dioxide and water by the overall reaction, _____ CO2 + ______ H2O -> C6H12O6 + _____ O2 (b) (12 pts) Show that glucose has _____ C-H bonds and ____ C-C bonds by drawing the structure of α-glucose below: (c) (13 pts) One can now estimate ∆Ho for glucose production by using the following simple bond equations (a) ______ + ______ -> C-H + O-O (∆Hoa = _____ kcal/mole) (b) ______ + ______ -> C-C + O-O (∆Hob = _____ kcal/mole) Thus (per mole of glucose formed), ∆Ho = (____)∆Hoa + (____)∆Hob = _______ kcal/mole Plant and animal call _______________ are able to release this amount of energy per mole of ____________ oxidized with ____________ under ______________ conditions.LAST NAME___________________________ First Name _______________________ Page 2 ________ 2. (30 points) While the thermodynamics appears simple, the kinetics of photosynthesis is very complicated, as you have seen in your text and in class. Many kinds of molecular structures are needed to successfully capture light and to catalyze the photosynthetic reactions. (a)(5 pts, 1 per blank) The _______________ membranes of chloroplasts have four kinds of large complexes: Two that absorb light, named _______________ and ______________ Two that don’t absorb light, named _____________ and _______________. (b) (25 pts) Draw the "Z" scheme showing how three of the above are involved in concentrating H+ ions (in lumen) needed by the fourth to make _________ from _______ + __________, and also in providing H- ions needed to convert _____________ to _____________ (in stroma).LAST NAME___________________________ First Name _______________________ Page 3 _______ 3. (40 points) Briefly describe the distinctive features of the 4 different membrane-bound complexes in chloroplasts: (a) The photosystem that produces O2 (10 pts) (b) The photosystem that reduces ferredoxin (10 pts) (c) The cytochrome-containing complex (10 pts) (d) The ATP-producing complex (10 pts)LAST NAME___________________________ First Name _______________________ Page 4 _________ 4. (35 points) Three of the membrane complexes in question 3 cooperate (along with small molecules) in moving electrons (e–) toward stroma and protons (H+), to create reducing power on the stromal side of the thylakoid membrane and acidity on the lumenal side. (a) Explain how NADPH and ATP are produced as a result of this electrochemical gradient. (20 pts) (b) Briefly explain how NADPH and ATP are used to synthesize glucose. (10 pts) (c) Briefly describe how the α and β forms of glucose are stored in plants. (5 pts)LAST NAME___________________________ First Name _______________________ Page 5 ________ 5. (40 points) The N-terminal signal sequences involved in protein targeting (translocation) to membranes fall into two classes: hydrophobic and amphipathic. (a) Briefly illustrate (or give an example of) each class. (10 pts) (b) Briefly illustrate how hydrophobic signal sequences target proteins to Rough Endoplasmic Reticulum (RER) membranes. (20 pts) (c) Briefly illustrate how amphipathic signal sequences target proteins to mitochondrial or chloroplast membranes. (10